The Asus Silent Square EVO heatsink looks like a big square block of cooling... and that description isn't too far off. The heatsink consists of two arrays of nickel plated aluminum fins which are wrapped around a 92 mm PWM fan buried within the body of the heatsink. The fan, a Sunon Maglev with Vapo bearings no less, draws air through intake cooling fins and expels it slightly warmer out through exhaust cooling fins on the opposite side.

FULL STORY @ FROSTYTECH(http://www.frostytech.com/articleview.cfm?articleID=2213)